SANAA, Yemen — Yemen's President Ali Abdullah Saleh arrived in the Saudi capital of Riyadh for treatment for wounds, the Saudi royal court said on Sunday.

"The Yemeni president has arrived along with officials and citizens who had received different injuries for treatment in Saudi Arabia," the royal court said.

The announcement followed a flurry of conflicting reports about the Yemeni president's whereabouts after Saudi King Abdullah announced that he had mediated a cease-fire to end deadly street battles.

Saleh was was wounded during an attack on the presidential palace Friday.

Saleh's abrupt departure threatened to deepen the crisis in his impoverished nation shaken by months of protests against his 33-year rule.

Saleh's Vice President Abd-Rabbu Mansour Hadi took over as acting president and supreme commander of the armed forces, Al Jazeera reported Saturday, citing unspecified sources. However, Saleh's son, Ahmed, being groomed as a successor, was believed to have stayed behind in an apparent bid to hold on to power.

John Brennan, President Barack Obama's national security adviser, spoke with the Yemeni vice president by telephone, a White House official said, but offered no details. The official spoke on condition of anonymity because of the sensitive nature of the situation.

For months, Saleh has defied intense pressure from his powerful Gulf neighbors and longtime ally Washington to step down. He agreed to transfer power several times, only to step back at the last moment. Should he leave the country now, he might never return, given that large segments of the population and a powerful tribal alliance could engineer his ouster while he's gone.

The extent of Saleh's injuries has been a matter of intense speculation. When the rocket struck the mosque in his presidential compound and splintered the pulpit, he was surrounded by top government officials and bodyguards. Eleven guards died, and five officials standing nearby were seriously wounded and taken to Saudi Arabia.

Yemeni ruling party officials and rebel tribesmen say Abdullah mediated a one-week cease-fire between the warring forces of Saleh and the anti-government opposition. The Saudi monarch intervened in an attempt to contain a raging military conflict that has swept the capital over the past week.

Abdullah stepped in shortly after Saleh's presidential palace compound was hit by a rebel rocket attack on Friday. Saleh was slightly injured, and 11 security guards were killed. Five other top officials were sent to Saudi Arabia for treatment.

Brink of civil warMeanwhile, thousands fled Sanaa on Saturday in fighting which has brought Yemen closer to civil war.

Saleh's forces retaliated by shelling the homes of the leaders of a powerful tribal federation fighting an urban battle to oust Saleh.

The clashes have killed nearly 200 people over the last two weeks and turned areas of Sanaa into ghost towns after residents fled for safety.

Global powers are worried that Yemen, home to al-Qaida in the Arabian Peninsula (AQAP) and bordering the world's biggest oil exporter Saudi Arabia, could become a failed state, raising risks for regional security and Gulf oil shipments.

Saleh, a tenacious political survivor who has clung to power for nearly 33 years, said in an audio address late on Friday that an "outlaw gang" was behind the attack, which he blamed on the Hashed tribe led by Sadeq al-Ahmar. A tribal spokesman denied responsibility.

"I salute our armed forces and the security forces for standing up firmly to confront this challenge by an outlaw gang that has nothing to do with the so-called youth revolution," Saleh said. "Seven officers were martyred."

'Bullets everywhere'
Tribal and medical officials said Saturday that 10 tribesmen were killed and 35 injured in overnight fighting in Sanaa's Hassaba neighborhood, headquarters of opposition Sheik Sadeq al-Ahmar. A tribal leader said street fighting lasted until dawn. Many of the compound's buildings and surrounding houses have already been heavily damaged by days of bombardment.

Government and rebel forces exchanged rocket fire, damaging a contested police station. The rockets rained down on streets housing government buildings that had been taken over by tribesmen.

Intermittent blasts and sporadic fire fights with automatic weapons punctuated the predawn hours and roads were clogged when the sun rose by civilians trying to flee the fighting that has engulfed more parts of the city.

Nearly 400 people have been killed since a popular uprising against Saleh began in January, inspired by the movements in Tunisia and Egypt that toppled their long-standing leaders.

The battles are being fought on several fronts, with popular protests in several cities and military units breaking away from Saleh to protect the protesters.

There has also been a nearly week-long campaign in Zinjibar by locals and Saleh's soldiers to oust Islamist and al-Qaida militants who seized the southern coastal city near a shipping lane where about 3 million barrels of oil pass daily.

Defying world pressure, Saleh has thrice reneged on a deal brokered by Gulf states for him to quit in return for immunity from prosecution, even as he loses support at home.

Reuters and The Associated Press contributed to this report.

Video: Embattled Yemen president to Saudi Arabia

Closed captioning of: Embattled Yemen president to Saudi Arabia

>>>a developing story tonight the embattled
president of yemen
accepted an offer from
saudi arabia
today to travel there for
medical treatment
after he was wounded yesterday in a rocket attack.
yemen
's vice president has reportedly taken over as
acting president
. all this is taking place after four months of mass protests in that country and could have major consequences. nbc's chief foreign correspondent
richard engel
has just landed in tunisia where the wave of protests in the
arab world
ended this year. richard, good evening.

>> reporter: good evening, lester. these are major developments in
yemen
. multiple saudi sources say that
yemen
's president of nearly 33 years,
ali abdullah saleh
, long backed by the
united states
, has already left
yemen
, leaving for
saudi arabia
where he's receiving
medical treatment
. he left after he was injured in a rocket attack on the presidential compound in sanaa yesterday. two rockets exploding inside the compound. according to the reports, he sustained injuries including extensive burns to his face and body. we have been able to learn also that the vice
president of yemen
is acting as the defacto leader of the country, the defacto president, also the head of the
armed forces
. yemeni officials are not confirming that he has left the country. but if he did, it's unclear that
yemen
's president would be strong enough to return and take over power and return to his office in
yemen
. if he does not return he will be the third arab leader to be removed since the arab spring began in tunisia.

A man prepares the grave of Hassan al-Hora during his funeral at a cemetery in Sanaa, July 19. Fighting between government forces and opposition supporters erupted in Yemen's capital Sanaa on Monday, killing six people, among them al-Hora, opposition sources said.
(Suhaib Salem / Reuters)
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Anti-government protesters shout slogans during a demonstration to demand the ouster of Yemen's President Ali Abdullah Saleh in the southern city of Taiz, July 19.
(Khaled Abdullah / Reuters)
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A girl has ''will not leave'' written on her face during a rally to support Yemen's President Ali Abdullah Saleh in Sanaa July 17.
(Suhaib Salem / Reuters)
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Anti-government protestors shout slogans during a demonstration demanding the resignation of President Ali Abdullah Saleh, in Sanaa, Yemen, on Wednesday, July 13.
(Mohammed Hamoud / AP)
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An anti-government protester writes slogans on a wall using his own blood during a rally to demand the ouster of President Ali Abdullah Saleh at Tagheer square in Sanaa on July 13. The words read "In my blood I protect Yemen."
(Suhaib Salem / Reuters)
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Girls light candles as they attend a rally to demand the ouster of Yemen's President Ali Abdullah Saleh in the southern city of Taiz July 9.
(Khaled Abdullah / Reuters)
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Supporters of Yemeni President Ali Abdullah Saleh sit on stone pillars during a rally in support of President Saleh in Sana'a, Yemen, on July 8. Supporters of Yemeni President Ali Abdullah Saleh staged rallies around his vacant palace Friday after their leader's first TV appearance since being injured in a blast last month and leaving for treatment in Saudi Arabia.
(Mohammed Al-Sayaghi / AP)
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A supporter of Saleh kisses his picture as his supporters celebrate in Sanaa on July 7 after he appeared on television for the first time since he was severely wounded in an assassination attempt.
(Mohammed Huwais / AFP - Getty Images)
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Saleh delivers a speech from the Saudi capital, Riyadh, on July 7, making his first public appearance since he was wounded in an attack on his palace in Sanaa in June.
(AFP - Getty Images)
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Anti-government protesters join their hands and shout slogans demanding an end to the 32-year regime of President Saleh, in Sanaa on July 6.
(EPA)
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A police vehicle is set ablaze during clashes between armed followers of the opposition and police in the southern city of Taiz on July 6.
(Khaled Abdullah / Reuters)
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A relative of victims of recent clashes talks to a member of the United Nations human rights investigation team, left, in Sanaa on July 5. The U.N. team arrived in Yemen last week to assess the situation in the country after months of unrest.
(Suhaib Salem / Reuters)
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Women recite prayers during a rally to demand the ouster of President Saleh in the southern city of Taiz on July 1. Tens of thousands of Yemenis turned Friday prayers into rallies for and against Saleh, who is recovering from injuries sustained in an assassination attempt in June.
(Khaled Abdullah / Reuters)
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Editor's note:
This image contains graphic content that some viewers may find disturbing.